From 7140449497e069dd12d4b4866daaad0143153be3 Mon Sep 17 00:00:00 2001
From: Anthony Wang
Date: Wed, 23 Dec 2020 14:21:17 -0600
Subject: Add sleeping.cpp

---
 20/dec/plat/sleeping.cpp | 47 +++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 47 insertions(+)
 create mode 100644 20/dec/plat/sleeping.cpp

diff --git a/20/dec/plat/sleeping.cpp b/20/dec/plat/sleeping.cpp
new file mode 100644
index 0000000..a7ad9f5
--- /dev/null
+++ b/20/dec/plat/sleeping.cpp
@@ -0,0 +1,47 @@
+#include <bits/stdc++.h>
+#define f first
+#define s second
+using namespace std;
+using ll = long long;
+using ii = pair<int, int>;
+const int MX = 3005, MOD = 1e9+7;
+
+
+ll s[MX], t[MX], DP[2][MX][2];
+
+
+int main() {
+	if (fopen("in", "r")) freopen("in", "r", stdin), freopen("out", "w", stdout);
+	ios_base::sync_with_stdio(0), cin.tie(0);
+
+	int N; cin >> N;
+	for (int i = 0; i < N; ++i) cin >> s[i];
+	for (int i = 0; i < N; ++i) cin >> t[i];
+
+	vector<ii> vc;
+	for (int i = 0; i < N; ++i) vc.emplace_back(s[i], 0);
+	for (int i = 0; i < N; ++i) vc.emplace_back(t[i], 1);
+	sort(begin(vc), end(vc));
+
+	DP[0][0][0] = 1;
+	for (int i = 0; i < 2*N; ++i) {
+		if (vc[i].s == 0) {
+			for (int j = 0; j <= N; ++j) {
+				(DP[1][j][1] += DP[0][j][0]) %= MOD;
+				(DP[1][j+1][0] += DP[0][j][0]) %= MOD;
+				(DP[1][j][1] += DP[0][j][1]) %= MOD;
+				(DP[1][j+1][1] += DP[0][j][1]) %= MOD;
+			}
+		}
+		else {
+			for (int j = 0; j <= N; ++j) {
+				(DP[1][j][0] += DP[0][j][0]) %= MOD;
+				if (j) (DP[1][j-1][0] += j*DP[0][j][0]) %= MOD;
+				if (j) (DP[1][j-1][1] += j*DP[0][j][1]) %= MOD;
+			}
+		}
+		memcpy(DP[0], DP[1], sizeof DP[1]);
+		memset(DP[1], 0, sizeof DP[1]);
+	}
+	cout << (DP[0][0][0]+DP[0][0][1])%MOD;
+}
-- 
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